More than a thousand users who had their Bitcoin investments locked up in the vaults of a Chinese exchange called GBL are re-evaluating their decision to do so today. GBL has disappeared from the Internet and taken $4.1 million worth of Bitcoin with it.

This doesn’t appear to be some sort of cyber heist like the one that occurred just last week, when nearly $2 million worth of Bitcoins was stolen from inputs.io. Instead it looks like GBL’s operators may have had this planned from the very beginning.

The loss is double frustrating for those who signed up with GBL early on. Today, a single Bitcoin is worth nearly three times what it was back in June.

What makes this case even more alarming is that GBL has only been operating for about six months.The company registered as a business in Hong Kong in June, but reports note that it never received a financial services license. That’s not enough to prevent anyone from operating a Bitcoin exchange, though, since many governments don’t even consider it to be real currency.

With no history or even a real, physical address that could be verified, GBL still managed to attract enough traders to amass a small fortune. Not long ago, warnings started popping up on Bitcoin forums that GBL might be a scam. Clearly they went unheeded by many users, who now have virtually no hope of getting back their missing Bitcoins.

China is one of the most active regions in the world when it comes to Bitcoin trading with more than $180 million traded every day. As in most other parts of the world, there are no regulations in place for virtual currencies yet. Couple that with the highly anonymous nature of Bitcoin (which makes it very difficult to trace), and you’ve got an attractive platform for connected criminals looking to make a fast buck.

If you’re trading Bitcoins, now might be a good time to re-evaluate where you’re trading and investigate other options for securely storing the contents of your wallet.